LUM final presentation Chanit Giat Rachel Stahl Instructor: Artyom Borzin Summer semester 2002

PROXY CACHE ENGINE The proxy cache engine gives hardware support to a server ’ s OS in order to improve its service rate, and adds security features. The main memory of a network server is the quick storage device, where the recently accessed data is saved. The system stores the information about all the files ’ mapping in main memory and calculates the exact path to the required file if present in main memory. If not present, orders the operating system to bring it from the storage device, and supplies the path to the free memory space is supplied. The system holds 2 main data bases: A main memory, which holds up to 2Meg paths to the server ’ s memory, and their aging parameters. A bit map table, which allows faster memory management by holding the free space image of the main memory.

Main functions: Search – returns the path to the main memory, or a path to a free space in the memory. Set attributes – sets the file ’ s aging attributes, as supplied by the OS. Delete – deletes a certain path from the memory. Count free – returns number of free path slots in the memory. Init – initialize the machine. (age – when number of records exceeds a specified number, the system cleans up some of them.) LengthCID=1ASISSite#Data SEARCH:

Previous uArchitecture Local Bus Interface Reg. file Data Stream controller Output FIFO Input FIFO Decoder CRC unit Database Manager (DBM) UTCAM SRAM (Bit Map)

uArchitecture changes: Doubling the front-end of the machine, including: Input FIFO Decoder CRC unit Buffering between the decoders and the DBM with a FIFO. The search for a free index in the Bit Map is now done in parallel to the rest of the command execution.

New uarchitecture LOCAL BUS INTERFACE Double FrontEnd1 DBM Fifo FrontEnd0 Input FIFO Decoder CRC Input FIFO Decoder CRC FIFOFIFO Reg. file Data Stream Controller Output FIFO DBMDBM

performance 2 input FIFOs – double rate receiving data from OS. 2 decoders – allows decoding of 2 commands in parallel. Significant for several long ‘ search ’ commands in a row. DBM FIFO – separates between the decoding and execution of commands, enables them to perform in parallel. Search for a free index now executes in parallel to other execution stages of a command. Saves ~50 clock cycles per ‘ search ’ command, which usually takes ~ cycles.

performance 2 search commands each with 102 bytes of path (on which crc is working): Old architecture New architecture Start execution (6202n) Decoding(1 st command) Start of simulation First command (718n) Second command (2380n) Decoding(2 nd command) Exe(1 st ) Finished execution (8560n) (718n)(2380n)(6128n)(9344n) (7868n) Exe(2 nd ) Finished execution (9486n) Decoding(2 nd command) Waiting (2 nd command) (14574n) ~190k commands per second ~110k commands per second